select a range of elements from a nested list

• To: mathgroup at smc.vnet.net
• Subject: [mg5387] select a range of elements from a nested list
• From: Oliver Schurr <schurro at gusun.acc.georgetown.edu>
• Date: Thu, 5 Dec 1996 14:50:24 -0500
• Sender: owner-wri-mathgroup at wolfram.com

```Hi MathGroup

Say you have a nested list like that {{x1,y1},{x2,y2},{x3,y3},...{xn,yn}}
basically containing X and Y values for a XY plot in each element. The X
values span a range from say 0 to 0.4 and you ONLY want to select the
elements (x,y values) from the list for which the x value spans say 0 to
0.3. BUT you don't want to COUNT the elements (visually on the screen) and
figure out the position at which the x value is just greater than 0.3 and
then subtract 1 from this position.

I still want do define the list by using

Table[list[[x,1]],list[[x,2]],{x, 1, ZZZ}]

here ZZZ means the number for which the x value <= 0.3, this number needs
to be found by MATHEMATICA!

I like to know if there is a general procedure to select elements from a
nested list based on the values of one member of the elements of that
nested list.

I hope I made myself clear enough to you all.

Thanks a lot.

Oliver Schurr
Department of Chemistry
Georgetown University
Washington, DC 20057

```

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